Retractor mechanism



FIG. 1 is a front view of the retractor mechanism;

FIG. 2 is a rear view thereof;

FIG. 3 is a left side view thereof, the right side view being a mirror image thereof,

FIG. 4 is a top view thereof, the bottom side view being a mirror image thereof; and,

FIG. 5 is a front side perspective view of the retractor mechanism.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a retractor mechanism, as shown and described. 